WoD groups usually have 1 or 2 trolls in it.
Last run I was in group A, The group B tank decided to stay out of the Belly and tried to fight the C tank for aggro on Cerberus from the back, he got aggro occasionally and caused the deaths of multiple people.
I was forced to jump into the Belly to counteract his stupidity (informing the A healers to keep me up). Luckily most DPS nuked the hell out of the adds and the healers let the B tank die and didn't res him. This way we survived by the skin of our teeth.

TL;DR there will always be trolls and stupid people everywhere. Don't let it get to you.